Phenylacetyl chloride → 1-[(Phenylacetyl)amino]cyclohexanecarboxylic acid phenylmethyl ester

1.21 g (12 mmol) of triethylamine was added to a solution of 2.33 g (10 mmol) of 1-aminocyclohexanecarboxylic acid phenylmethyl ester in 100 ml of tetrahydrofuran, and 1.55 g (10 mmol) of phenylacetyl chloride was added dropwise thereto under ice-cooling, followed by stirring of the mixture overnight. The reaction mixture was concentrated under reduced pressure, ethyl acetate was added thereto, and the mixture was successively washed with water, a 10% aqueous potassium hydrogen sulfate solution, a saturated aqueous sodium hydrogencarbonate solution and saturated brine, followed by drying with anhydrous sodium sulfate. After the solvent was distilled off under reduced pressure, the residue was purified by silica gel chromatography to obtain 3.21 g (91%) of the title compound.